Mechanical stripping device



P. D. NIELSEN MECHANICAL STRIPPING DEVICE Filed Deo.

March 3l, 1942,

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arch 3l, E942. -p D NIELSEN MECHANICAL STRIPPING DEVICE 5 Sheets-,Sheet 2 Filed Dec. 5l, 1940 arch 3l, 1942.

P. D.y NIELSEN MECHANICAL STRIPPING DEVICE I 5 Sheets-Sheet 3 Filed Dec. l31, 1940V March 31, 1942. P. D; NIELSEN 2,278,16

MECHANICAL STRIPPING DEVICE I Filed Deo. 3l, 1940 5 Sheets-Sheet 4 i "U F155.w

Y P11-gi. /V/ELSEN,

March 31, *1942.

P. D. NIELSEN MECHANICAL STRIPP ING DEVICE Filed DeC. 5l, 1940 5 Sheets-Sheet 5 PEE/e? y' 0. /V/gLSE/v,

Patented Mar. 315.1942

reeln. meinen, Lema, ohio,

`tional Tube Compan 'a corporation of- New Jersey assigner to Na- Application December 31, l1944i, Serial No. 312,629

6 Claims. (Ci. 22-95) clearancey is provided to facilitate The present invention relates to improvements in stripping devices which, while not limited stripping ingots from from a poured ingot thereto, arewell suited for their molds or core bars mold flask assembly.

The invention provides improved means to enable the removal of an ingot from its mold, or the removal of a core arbor from a poured ingot v'mold assembly. .Howeven the device may be used in other environments, as will be apparent from the following disclosure.

One object of the invention is to provide a stripping device which will translate the weight vr,of the object being 'stripped into the force re- -fquired for strippingv by the provision of a lever system, so constructed and arranged as to require very little headroom for its operation.

Another Objectis to provide a compactly assembled lever system for use in a stripping mechanism which, when suspended from an overhead traveling crane, will be capable of easy, quick, and reliable operation in congested locations.`

The above `and other features of the invention as defined with particularity in the appended claims, will be -fully apparent from consideration of the following detailed disclosure when read in connection with the accompanying drawings, in which:

Figure 1 is a side device:

Figure 2 is an end elevation thereof;

Figure 3 is a view showing the stripper suspended from an overhead crane and engaged in initial stripping position with an ingot and ingot mold;

Figure 4 is a similar view showing the stripper suspended from an overhead crane and engaged in stripping position with a pouredingot mold flask assembly; A

Figure 5 shows the position vof the parts at an intermediate stage in the operation;

Figure 6 shows the position of the parts at the end of the stripping stroke.

elevation of the Vstripping ping operation, easy withdrawal of the mold from the ingot or the ingot mold flask assembly from the core bar. However, irregularities of the surface of the ingot or core bar and the conning ingot mold or ingot mold ask assembly are usually of such a magnitude that, in .addition to providing a very large force to break the ingot or core bar loose to initiate movement, a stripping 'force of lower magnitude must still be applied for a length of stroke sufiicient that the increase in dimensions of the coniining ingot mold or ingot 'mold ask assembly, as provided by the taper,

is suiiicient to permit ,easy withdrawal oi the ingot or core bar.

Heretofore it has been common practice to construit stripping devices with a stripping force suicient to break the object loose from the mold, this same force being maintained available for the entire stripping stroke. Stripping forces for this purpose are commonly developed by hydraulic pushers, motor operated screws, motor operated cable systems, or simple lever systems. no attempt'heretofore having been made to take advantage of the factthat a considerably lesser stripping force is required once stripping movement is initiated.

Advantage of this difference in stripping force requirement is taken in carrying out this invention for the purpose of achieving compactness in construction and minimum requirement of headroom for successful operation.

Y The stripping device comprises a spreader I which is suspended from hook H of a crane C, a body or housing 2 which provides a support for the various`levers and contains the various ftulcrums around which the levers move, con- Very large forces are required to initiate stripl from their molds, or core bars ingot mold ask assembly. However, after initially breaking the ingot loose from the mold, or thecore bar loose from the poured ingot mold ilask assembly, a considerably. reduced force is sufiicient to continue stripping. The reason for the reduction in stripping force required for stripping after the ingot or core bar has broken loose and moved a small distance, is that core bars and ingots-are tapered,

ping of ingots froxna poured necting rods 3 which link thelever system to the spreader I, arms 4 and l which provide an adjustable means of attaching the stripping device to the cheek section of an ingot mold ilask assemblyor'to an ingot mold, and a. block or bullnose -8 for engaging the ingot core arbor or other object to be stripped.A

The lever system includes two levers I and 9 and connecting rod 8. The lever 1 is provided with pins I0 and II disposed to be engaged in grooves I5 and I6Vin body section 2. Lever 9 is provided lwith a fulcrum at point I2. The connecting rod 8 connects levers 'I and 9 together at points Il and I3 respectively. The outer end of lever 9 is attached to connecting rod S at point I8 and the outer end of lever I is connected to arm 4 at point I1.

` se that, with continued movement in the strip- The improved stripping device isyspecically about fulcrum i I.

constructed to .translate the weight of the ob- `iect being stripped into the stripping force required to accomplish stripping. It is thus particularly suited for stripping such heavy objects as ingots from ingot molds'and core bars from ingot mold ask assemblies where the. weight involved `is considerable and of suicient magnitude to provide, within the limits of the capacity of the device for multiplying this weight, sufiicient force to accomplish stripping.

A particular advantage inherent in the novel device herein claimed is that no outside sourceof power "is required to develop the force necessary for stripping, all the force required being developed from the weight of the object being stripped. The lever system of the stripping `device is designed with a mechanical advantage movement, the lever I thereupon begins to move about pin Il as a fulcrum. At this stage of the stripping stroke the overall mechanical advantage of the system is V(1 to 1) )((255 to 1) :2t/2 to 1. Y

As has previously been pointed out, the force l required for stripping after stripping is initiated which multiplies the weight of the object being i stripped and translates this weight into stripping force suicient to accomplish stripping without the need for any outside source of power. Furthermore, the load on the crane or similar device on which this stripping device is suspended while in use is entirely independent of the stripping force developed, the load on the crane never exceeding the combined weight of the stripping device and the objects to which it is attached for stripping.

Another particular advantage of the novel stripping device as dened in the claims, is the compact construction which facilitates its use in thevery congested areas where stripping operations must frequently be performed. Although the same stripping force could be developed by a stripper having two single lever arms," such construction Ywould necessitate single lever arms of such length, for the same developed force, as to make the device cumbersome and awkward to handle and would thereby require considerable space for satisfactory operation. The provision of means' for shifting the fulcrum in one of the lever arms has the very desirable advantage of reducing the headroom required for operation. This is an important consideration where it is desired to strip objects of considerable length, using cranes with limited headroom for operating the stripping device. Figures 4, 5, and 6 illustrate this feature. Figure 4 shows the stripping device attached to a poured ingot mold askassembly at the beginning of the stripping stroke.

Figures 5 and 6 are similar illustrations, Figure 5 showing the position ofthe lever arms at that interval or stage of the stripping stroke where lever I has just completed its movement about ulcrum Il) and is about to continue movement about fulcrum II, and Figure 6 showing the position of the lever arms at the end of the stripping stroke.

In Figures 4, 5, and', the scale of thedrawin'gs shows that a mechanical advantage of 2l/2 to 1 is indicated for lever 9 about fulcrum I2. Similarly a mechanical advantage of 3 to 1 is indicated for lever 'I about fulcrum Il and a mechanical advantage of 1 to 1 of this same lever I cal advantage is maintained during the initial.

stripping stages or until the position illustrated Vin Figure 5 is reached. Upon further stripping 75 is much reduced, and under the present invention advantage is taken of this fact to'reduce head- 10.

'of levers recited in the foregoing paragraph has a stripping movement of 2 inches between the positions shown in Figures 4 and 5.` Coincident with a stripping movement of 2 inches, the spreader bar I is raised 7 2=l5 inches. Similarly, between positions shown in Figures 5 and 6, the stripping movement is 6 inches and, as the mechanical advantage at this stage of the stroke is 21/2 to 1, the coincident movement of spreader barfor a 6inch stripping stroke is 25/2x6-f15 inches. Thus it is seen that with the double fulcrum multiple lever system I can accomplish a stripping stroke of 8 inches with a rise of the spreader bar of 30 inches whereas, had a mechanical advantage of '7l/2 to 1 been maintained for the entire stripping stroke of v8 inches, the rise of the spreader bar would have been 'l1/2 X8"=60 inches. In the example referred to, the described construction has resulted in a conservation of 30 inches of spreader bar travel to secure the same stripping stroke as could have been accomplished had the mechanical advantage of l1/2 to 1, which is required to initiate stripping, been acting over the entire stripping stroke. Thus the headroom requirements for stripping has been reduced by a similar amount, namely, 30 inches.

The stripping forcesdeveloped by this stripping device when having the proportions above recited are such that if the object being stripped has a weight of 10 tons, the stripping force developed in that portion of the stroke having a.

While I have described quite precisely the de-' tails of a specific embodiment of the invention herein illustrated, it is to be understood that the drawings and description are to be interpreted in an illustrative rather than a limiting sense, since various modiflcations may be made without departure from the invention as defined in the appended claims.

I claim: x

1. A stripping device f or separating nested objects from one another, comprising a spreader supported from overhead, a frame movable relatively thereto andV having an abutment for engagement with one of the objects to be separated, a multiple lever system carried by the frame and arranged so as to provide a dual set of fulcrums which come into play at different times to effect a change in the mechanical advantage of the system whereby the magnitude of the stripping force exerted to separate said nested objects is greatest during the initial stage of the stripping stroke and decreases thereafter.

2. A stripping device for separating nested objects from one another, comprising a spreadersupported from overhead, a frame movable relatively thereto and having an 'abutment for engagement with one of the objects to be separated,

and a multiple lever system carried by the frame agrarie lgreatestlduring the initialstage oi the stripping stroke and decreases thereafter.

3. A stripping device for separating nested objects from one another, comprising a spreader supported from overhead, a lframe movable relatively thereto and having ari-abutment fior engagement with one4 of the objects to be separated, and a multiple lever system carried by the :trarne and having one connecting member coupled with said spreader and another engaged with the otherof said nested objects, there being means provided iorl shifting the iulcrum points of certain levers of the system so as to provide the greatest mechanical advantage at the initial stage of the stripping stroke with a decreasing mechanical advantage as the stripping stroke proceeds.

d. A stripping device for separating nested obitiallt stage of the stripping stroke and decreases as the stripping stroke proceeds.-

5. A stripping device of the character described, comprising a vmember adapted to be suspended from an overhead crane, a frame having an object-engaging'portion for coaction with one of two objects to be separated, a pair of fixed-iulcrum levers mounted on said frame and having respective links connecting them with said member, a pair of multip1e-iulcrum levers,

respective means operatively connecting the latter with said iixed-iulcrum levers, and means for coupling said variable-fulcrum levers with the other ci said objectsy to be separated, said frame having formed therein a plurality of fulcruming points for each of said variable-fulcrurn levers.

6. A stripping device of the character described, comprising a member adapted to be susjects from one another, comprising4 a spreader supported from overhead, a :trame movable relatively 'thereto and having an abutment for engagement with one or the objects to be separated, and a multiple lever system carried by the frame, one connecting member coupling said sys,-1k tem with one oi said nested objects, another con necting member connecting said system with said Sii spreader, said system including a lever carrying two iulcrum pins and said frame having two inlvcrurn. notches adapted ior alternate coaction with said two pins, whereby the mechanical advantage of the system is greatest during the inpended trom an overheadcrane, a frame having an object-engaging portion for coaction with one of two objects to be separated, a-pair of xedfulcrum levers mounted on said frame and having respective links connecting them with said member, a pair of variahle=fu1crurn levers each carrying two fulcrum bearing pins, respective iinhs connecting the latter with said fixed-fulcrum levers, and means for coupling said variable-fulcrum levers with the other oi said objects to he separated, said frame having a plurality of pairs of notched seats formed therein fpr coaction with the said fulcrum hearing pins, wheres icy the mechanical advantage or the assemblage isvaried during the stripping stroke of the device. a

PEER. D. LSEN; 

